Sewing machine cooling system

ABSTRACT

A cooling system for an industrial sewing machine of the overseaming type, including a hollow, shell-like shroud positioned over and closely surrounding the sewing machine housing, and a fan mounted on the machine&#39;&#39;s main drive shaft adjacent an opening in the shroud to force air through the shroud over the outer surface of the machine and out through open spaces along the bottom of the shroud and at the end of the machine opposite the fan. The shroud being spaced from the surface of the machine is cool to the touch and assists in muffling the sound of the machine.

United States Patent Armstead, Jr. et al.

[541 SEWING MACHINE COOLING SYSTEM [72] Inventors: George B. Armstead, Jr., Glastonbury; Ed-

ward A. Kelly, Wethersfield, both of Conn.

[73] Assignee: The Merrow Machine Company, Hartford,

Conn.

[22] Filed: Mar. 10, 1970 211 App1.No.: 18,062

[ 1 Feb. 1,1972

Primary Examiner-H. Hampton Hunter AnarneyBeveridge & DeGrandi [5 7] ABSTRACT A cooling system for an industrial sewing machine of the overseaming type, including a hollow, shell-like shroud positioned over and closely surrounding the sewing machine housing, and a fan mounted on the machine's main drive shaft adjacent an opening in the shroud to force air through the shroud over the outer surface of the machine and out through open spaces along the bottom of the shroud and at the end of the machine opposite the fan. The shroud being spaced from the surface of the machine is cool to the touch and assists in muffling the sound of the machine.

9 Claims, 4 Drawing Figures PAIENIED FEB 1 B72 SHEET 1 0F 2 INVENTOQS GEORGE B. ARMSTEAD, 1R, EDWARD A KELLY av May. 4 SQ firawuL-L JUN ATTORNEYS PATENTED FEB I 37? SHEET 2 0F 2 GEORGE B. ARMSTEAD, UR. EDWARD A. KELLY Y 4 Ya ATTORNEY") SEWING MACHINE COOLING SYSTEM This invention relates to sewing machines, and more particularly to an improved cooling system for high-speed indus trial overseaming machines.

While industrial overseaming machines, such as the wellknown Merrow machines, are capable of sustained operation at relatively high rates, such operation generates substantial heat and difficulty has been encountered in the past in adequately cooling various components of the machine. This problem has been aggravated in recent years by the continuous demand by industry for increased operating speeds which have been made practical, in part, by the development of highstrength synthetic threads which greatly reduce the problem of thread breaking even at the higher speeds, and by the use of automatic trimming equipment which permits substantially continuous operation of the machine in many operations. To reduce friction and help dissipate heat, such machines are normally equipped with a self-contained, circulating, oil lubricating system such as that illustrated, for example, in U.S. Pat. No. 2,879,733.

Attempts have been made to cool overseaming sewing machines by employing a fan positioned in a recess in the machine frame and mounted on the main drive shaft for rotation therewith, and by forming cooling fins on the surface of the recess in the path of air from the fan to assist in carrying away heat generated in the main machine bearing. Such a cooling arrangement is illustrated, for example, in U.S. Pat. No. 2,704,042. However, the cooling effect of such fans are minimal due, in part, to the fact that the air from the fan only contacts a very limited portion of the frame at the end thereof. Further, the use of fanstends to create objectionable air currents which seriously interfere with the thread being fed to the machine, particularly when a number of very fine synthetic threads are used, making it necessary to keep the air moved by the fans at a minimum.

As indicated above, the lubricating systems of machines of this type are normally self-contained so that heat may only be dissipated from the machine housing frame by radiation and convection. The heat is generated primarily in the machines bearings and cam mechanism, and is absorbed and distributed by the circulating lubricant and is ultimately dissipated by the machine frame. While the rate of such heat dissipation is normally sufficient during proper functioning of the lubricating system to prevent heat damage to the working parts of the machine, the heat buildup during sustained operation may be sufficient to be objectionable both from the standpoint of safety and anxiety of the machine operator and of the mechanic tending the machine.

Applicant has found that a relatively small volume of cooling air flowing over the surface of the machine will provide adequate cooling provided that the flow of air is confined closely to and caused to flow over the major portion of the outer surface of the machine frame. Applicant accomplishes this, while avoiding interference with the thread caused by excessive air currents, by using a small fan mounted directly on the main drive shaft of the machine, at the end thereof opposite the sewing mechanism, to be driven with the machine. A contoured housing, or shroud having an opening therein adjacent the fan is positioned over, and covers the machine frame to confine the flow of air closely around the outer surface of the frame. Air is permitted to escape from the shroud along the front and back edges of the machine adjacent the bottom thereof, and at the end of the shroud opposite the fan, in areas where the flow of air will not interfere with the sewing operation or thread feeding. By confining the flow of air to the relatively close spacing between the machine frame and the shroud, a relatively small volume of air is required to adequately cool the machine. In addition, the spacing of the shroud from the surface of the machine housing results in the shroud being substantially cooler than the housing, under normal operating conditions, thereby eliminating any hazard to the operator and avoiding any apprehension on the part of the operator that the machine is overheating.

It is therefore an object of the present invention to provide an improved cooling system for overseaming machines.

Another object of the invention is to provide a cooling system employing a fan to direct air over the surface of an overseaming machine, and a shroud to confine the flow of air closely over the machine housing.

Other objects and advantages of the machine will become apparent from the following detailed description, taken in conjunction with the drawings, in which:

FIG. 1 is a front elevation view of an overseaming machine embodying the invention, with certain parts omitted for clariy;

FIG. 2 is a vertical sectional view taken on line 22 of FIG. 4 and illustrating the cooling system structure, with the machine being shown in phantom;

FIG. 3 is a sectional view taken on line 3-3 of FIG. 2; and

FIG. 4 is an end elevation view of the cooling system.

Referring to the drawings in detail now, an overseaming machine embodying the cooling system of the present invention is indicated generally by the reference numeral 10 and includes a relatively thin, molded shroud 12 mounted on a sewing machine 14 of the general type illustrated, for example, in U.S. Pat. No. 2,93l,328. Machine 14 is illustrated in phantom line in FIGS. 2-4, and includes a housing, or frame, 16 which contains the usual drive mechanism for the machines work feed and stitch-forming mechanism (not shown) at the left end of the machine, as viewed in FIG. 1. The machine is driven in the conventional manner by a drive sheave 18 mounted on the machines main drive shaft 20 projecting from the right end of frame 16, again viewed in FIG. I. Sheave 18 is driven by a conventional V-belt 22 by an electric motor, not shown. A multiple bladed fan 24 is mounted on shaft 20, adjacent sheave 18, for rotation therewith, and the usual handwheel 26 is mounted on the end of shaft 20 in outwardly spaced relation to fan 24.

Shroud 12 is preferably molded as a unitary structure from a single homogeneous mass of impact resistant, high-strength plastic, or synthetic resin material, and is shaped to conform closely to the overall profile of the machine frame as indicated in FIGS. 2-4. Alternatively, the shroud may be reinforced by laminating a glass fiber fabric in the plastic, or it may be formed of metal as by die casting from aluminum or zinc. An opening 28 in the general shape of an inverted U is formed in the end wall 30 of shroud 12 in position to fit over handwheel 26. As seen in FIGS. 2 and 3, wall 30 is spaced from fan 24 to act as a safety shield to assure that an operator will not inadvertently get a finger caught in the fan 24 by placing her hand on the wheel 26 while the machine is operating. The opening 28 is sufiiciently large so that the open space below and around the periphery of wheel 26 will permit fan 24 to draw sufiicient air into the shroud to create a flow of cooling air over the frame between its outer surface and the inner surface of shroud 12. As shown in FIGS. 3 and 4, if desired a screen 31 may be mounted, as by screws 33 and brackets 35 on shroud 12 between the handwheel 26 and fan 24 in position to act as a further safety shield. As indicated in FIG. 1, shroud 12 is rigidly mounted on and held in fixed spaced relation to frame 16 by a plurality of screws 32.

The forward wall 34 of shroud 12 is preferably spaced very close to the machine frame 16, as indicated in FIG. 3, to restrict the amount of cooling air flowing over the forward surface of the frame. This restricted airflow over the front portion of the machine is desirable to insure against excessive air currents in the work area in front of the machine. Further, wall 34 preferably terminates in an edge 36 spaced above the bottom of the machine to permit air to escape along the bottom edge of wall 34 throughout the length of the frame. Similarly, the rear wall 38 of shroud l2 terminates in an edge 40 spaced above the base of the machine. Dust shield 42 on the forward surface of the machine 14 limits the escape of cooling air from the end of the shroud adjacent the stitch-forming mechanism along the end of wall 34; however, as seen in FIGS. 2 and 3, cooling air is permitted to escape from the end of the shroud along the top wall 44 and the backwall 38.

As seen in FIG. 1, the top wall 44 of shroud 12 forms a convenient mounting surface for a plurality of thread tensioning guides 46. Also, openings may be provided in the various surfaces of the shroud as necessary. For example, an opening 48 is provided to permit access to the conventional oil sight glass of the machine, and a second opening 50 is provided to permit movement of thread takeup 53. A removable threading plate 52 is mounted over an opening in wall 34, and openings are provided in the top wall 44 for the oil filter assembly 54 and the oil bubbler pipe cap 56.

From the above, it should be apparent that the molded shroud 12 provides a relatively thin air duct, or channel surrounding frame 16 so that a relatively low volume of cooling air is necessary to provide adequate cooling for the machine. Although a relatively low volume of cooling air is required, the close spacing between the machine and shroud results in a relatively high velocity of the air, thereby producing a highly efiicient cooling for the machine. Further, the spacing between the shroud and the metal frame results in the outer surface of the shroud being substantially cooler than the frame itself, with the result that the shroud feels cool to the touch so that any anxiety by the operator that her machine is running too hot is effectively eliminated.

The more uniform cooling of the machine frame also makes it possible for the machines lubricating system to do a more efficient job of transferring the heat to the frame. When only radiation and convection was relied on to dissipate the heat, many areas of the frame's outer surface were relatively inefficient. However, by spraying or otherwise dispersing the lubricant over the inner surface of a frame which is more uniformly cooled, the lubricant is maintained at a lower temperature and therefore provides better lubrication and more adequate cooling. Also, in the event of a local hot spot, or area of the frame which requires greater cooling, the outer surface of the frame may readily be provided with cooling fans without in any way altering the aesthetics of the machine.

While we have disclosed a preferred embodiment of our invention, we wish it understood that we do not intend to be restricted solely thereto, but that we do intend to include all embodiments thereof which would be apparent to one skilled in the art and which come within the spirit and scope of our invention.

We claim:

1. In an overedge sewing machine including a frame, a stitch-forming mechanism at one end of said frame, a drive shaft journaled within said frame and projecting outwardly therefrom at the end thereof opposite said one end, and a drive sheave mounted on the outwardly projecting portion of said drive shaft, the improvement comprising, a fan mounted on said drive shaft adjacent said sheave for rotation therewith,

a shroud having an open end, said shroud covering said fan and extending over said frame, means mounting said shroud on said frame in closely spaced relation thereto with said open end of said shroud positioned adjacent said one end of said frame, said shroud cooperating with said frame to define a thin air duct extending over and covering a major portion of the outer surface of said frame, and an opening in said shroud in the end thereof adjacent said fan to permit air to be drawn therethrough and impelled through said air duct and directed over the said major portion of said outer surface of said frame to cool said machine.

2. In an overedge sewing machine according to claim 1, the further improvement wherein said shroud has a cross section in the general shape of an inverted U in a plane perpendicular to said drive shaft and wherein the lower edge of at least one sidewall of said shroud is spaced from said machine frame to define an elongated open slot providing an exit for cooling air along the lower edge of said at least one wall at the bottom of said frame.

3. In an overedge sewing machine according to claim 1, the further improvement comprising a handwheel mounted on the end of said drive shaft and projecting outwardly from said opening, said handwheel forming a guard to protect an operators hands from engaging said fan through said openin 4. In an overedge sewing machine according to c arm 3,

wherein said means mounting the shroud on said frame supports said shroud in position with the spacing between said frame and the front wall of said shroud being less than the spacing between said frame and the top and rear walls of said shroud whereby a greater volume of cooling air may flow over the top and rear portions of said frame.

5. In an overedge sewing machine according to claim 3, the further improvement wherein said shroud is molded as a unitary structure from a synthetic resin material.

6. In an overedge sewing machine according to claim 5, the further improvement comprising a plurality of thread tensioning members mounted on said shroud.

7. in an overedge sewing machine according to claim 3, the further improvement wherein said shroud has formed therein a plurality of access openings to provide observation of and access to essential components of the machine while said shroud is mounted on said machine.

8. In an overedge sewing machine according to claim 3, the further improvement wherein said shroud is formed from metal by die casting.

9. In an overedge sewing machine according to claim 3, the further improvement comprising a screen mounted between said fan and said opening. 

1. In an overedge sewing machine including a frame, a stitchforming mechanism at one end of said frame, a drive shaft journaled within said frame and projecting outwardly therefrom at the end thereof opposite said one end, and a drive sheave mounted on the outwardly projecting portion of said drive shaft, the improvement comprising, a fan mounted on said drive shaft adjacent said sheave for rotation therewith, a shroud having an open end, said shroud covering said fan and extending over said frame, means mounting said shroud on said frame in closely spaced relation thereto with said open end of said shroud positioned adjacent said one end of said frame, said shroud cooperating with said frame to define a thin air duct extending over and covering a major portion of the outer surface of said frame, and an opening in said shroud in the end thereof adjacent said fan to permit air to be drawn therethrough and impelled through said air duct and directed over the said major portion of said outer surface of said frame to cool said machine.
 2. In an overedge sewing machine according to claim 1, the further improvement wherein said shroud has a cross section in the general shape of an inverted U in a plane perpendicular to said drive shaft and wherein the lower edge of at least one sidewall of said shroud is spaced from said machine frame to define an elongated open slot providing an exit for cooling air along the lower edge of said at least one wall at the bottom of said frame.
 3. In an overedge sewing machine according to claim 1, the further improvement comprising a handwheel mounted on the end of said drive shaft and projecting outwardly from said opening, said handwheel forming a guard to protect an operator''s hands from engaging said fan through said opening.
 4. In an overedge sewing machine according to claim 3, wherein said means mounting the shroud on said frame supports said shroud in position with the spacing between said frame and the front wall of said shroud being less than the spacing between said frame and the top and rear walls of said shroud whereby a greater volume of cooling air may flow over the top and rear portions of said frame.
 5. In an overedge sewing machine according to claim 3, the further improvement wherein said shroud is molded as a unitary structure from a synthetic resin material.
 6. In an overedge sewing machine according to claim 5, the further improvement comprising a plurality of thread tensioning members mounted on said shroud.
 7. In an overedge sewing machine according to claim 3, the further improvement wherein said shroud has formed therein a plurality of access openings to provide observation of and access to essential components of the machine while said shroud is mounted on said machine.
 8. In an overedge sewing machine according to claim 3, the further improvement wherein said shroud is formed from metal by die casting.
 9. In an overedge sewing machine according to claim 3, the further improvement comprising a screen mounted between said fan and said opening. 